Sum bug?
lazarus / 64-FPC development

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bytebites · 2024-03-11 21:38

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
sumbug;{$mode delphi}{$ModeSwitch anonymousfunctions}{$ModeSwitch
functionreferences}type { tfoo }  tr=record 
 x,y:integer; end;  tf=reference to procedure(i:tr);  tfoo=class 
procedure repe(f:tf);end; { tfoo } procedure tfoo.repe(f: tf);var  r:
tr;  i: Integer;begin  for i:=1 to 5 do begin    r.x:=i;    f(r) 
end;end; procedure test;var  foo: tfoo;  c: Integer;begin 
foo:=tfoo.create;  c:=0;  foo.repe(procedure (i:tr) begin   
c:=c+i.x;    writeln(i.x)  end);   writeln('sum ',c);end;begin 
test;end. 
This code outputs sum 0 when optimization is 3 or 4.

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Thaddy · 2024-03-12 05:38

Can' t reproduce. Note you never free Tfoo so the example leaks
memory. That can be the cause on higher optimization levels.
Tested Windows11, x86-64 and Debian bookworm x86_64 with trunk from
Sunday.
Note I fixed the bug *before* testing because it was so obvious.

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cdbc · 2024-03-12 06:12

Hi
With bug-fix in place, I can reproduce in -O3 & -O4 -> sum = 0.
Fwiw, mode delphi or objfpc doesn't matter, neither does freeing
foo...
edit: Compiler compiled on january 28 2024:
QuoteFree Pascal Compiler version 3.3.1-15019-g664f8fc2ba-dirty
[2024/01/28] for x86_64
Copyright (c) 1993-2024 by Florian Klaempfl and othersRegards Benny

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Thaddy · 2024-03-12 06:46

Yes I can now reproduce it. I had heaptrc on. Plz report a bug. And
yes 3 and 4 both have the bug, O2 is fine.

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rasberryrabbit · 2024-03-12 11:59

It's LOADMODIFYSTORE bug. Compiler switch {$Optimization
NOUSELOADMODIFYSTORE} make avoid problem.

I also reproduce with FPC trunk.

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Thaddy · 2024-03-12 12:52

Yes, you are correct. {$Optimization NOUSELOADMODIFYSTORE} works.